Creswell, J. W. Research Design 4ed. Sage.
Lua i Stíl Chicago (17ú heag.)Creswell, John W. Research Design 4ed. Sage.
Lua MLA (9ú heag.)Creswell, John W. Research Design 4ed. Sage.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.